- Dilophosaurus was a theropod dinosaur from the Early Jurassic Period. The name means 'two-crested lizard', because the animal had two crests (Greek di meaning 'two', lophos meaning 'crest' and sauros meaning 'lizard'). The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name. Dilophosaurus is one of the earliest known Jurassic theropods, but also one of the least understood. The most distinctive characteristic of Dilophosaurus is the pair of rounded crests on its skull, possibly used for display. Studies show that these crests may have been larger in one sex than in the other. The teeth of Dilophosaurus are long, but have a fairly small base and expand basally. Another skull feature was a notch behind the first row of teeth, giving Dilophosaurus an almost crocodile-like appearance, similar to the putatively piscivorous spinosaurid dinosaurs. This "notch" existed by virtue of a weak connection between the premaxillary and maxillary bones of the skull. This conformation led to the early hypothesis that Dilophosaurus scavenged off dead carcasses, with the front teeth being too weak to bring down and hold large prey.